Drawing press mechanism



March 6, 1934. A. BERTUCCI 1,949,407

DRAWING PRESS MECHANISM Filed June 25 1930 2 Sheets-Sheet 1 mmm j y swATTORNEY w BY March 6, 1934. A. BERTuccl 1,949,407'

DRAWING PRESS MECHANISM Filed June 25, 1930 2 Sheets-Sheet 2 ZT- jg 2 l45 44 f l f l f )j 4f 37 Patented Mar. 6, 1934 UNITED STATES PATENTOFFlCE DRAWING PRE S S MECHANI SM Application June 25, 1930, Serial No.463,726

3 Claims.

The present invention relates to a drawing press mechanism and hasparticular reference to a safety device therefor.

The principal object of the present invention is the provision of adrawing press mechanism utilizing instrumentalities for removing thedrawn work from the dies after the drawing operation, theseinstrumentalities beingactuated in a manner to permit suspension of theknockout operation in the event of abnormal conditions.

An important object of the present invention is the provision of adrawing press mechanism embodying a safety device for protecting theworking parts of the press against damage during abnormal drawingconditions,

An important object of the present invention is the provision of aknockout mechanism for a drawing press which is provided with safetydevicesfor altering the knockout operation in the event of abnormalconditions.

An important object of the present invention is thevprovision of aknockout mechanism for a drawing press which is provided with safetydevices for stopping the operation of the press in the presence ofabnormal conditions.

The present invention contemplates the use of a safety device embodyingactuating'devices for knockout instrumentalities which normally movethrough a given cycle of operation but which change this cycle ofoperation in the presence oi abnormal knockout conditions.

Numerous kother objects of the invention will be apparent as it isbetter vunderstood. from the following description, which, taken inconnection with the accompanying drawings, discloses a preferredembodiment thereof.

Referring to the drawings:-

`Figure l is a schematic drawing, partly in side elevation and partly insection ofparts of a drawing press mechanism embodying the presentinvention.

Fig. 2 is a view similar to Fig. 1 illustrating the parts inthe-position assumed during an abnormal condition.

Fig. 3 is a sectional detail of a locking unit for holding the safetydevice parts in position, the View being taken along the line 3-3 inFig. 2.

The safety features of the present invention may be applied to the usualform of drawing press mechanism utilizing standard die construction, theoperation of the safety feature aiecting the work done by the knockoutinstrumentalities of such a mechanism.

The cooperating die members of the press preferably comprise a die plate21 supporting parts of the lower or stationary elementsbf the diemembers, these including a cutedge member 22 and an anvil 23, bothmounted upon the die plate 21. A cutting wall 24 formed in the cutedgemember 22 is spaced from and is concentric with the outer face of theanvil 23 and a draw ring 25 is adapted to have sliding movement betweenthe anvil and the cutedge member. This draw ring is or may be supportedon the upper ends of pins 26 connected with the usual drawing cushionnot shown.

The upper die members include a punch member 27 having a stem 28 clampedin a punch block 29 secured in a usual or a preferred manner to a slidehaving vertical movement relative to the frame 31 of the pressmechanism. A knockout pad 32 is adapted to normally rest within anopening 33 formed in the lower end of the punch member 27 and is carriedby a vertical knockout rod 34 extending through a vertical bore 35formed in the punch member.V A spring 36 surrounds the upper end of therod 34 and is interposed between the upper end of the stem 28 andlocknuts 37 threadedly engaging the rod.

Actuating devices foroperating the knockout pad through its knockout rod34 are provided, one element of which is carried bodily by the punchblock 29 and, therefore, this element moves up and down with the punchmember 27. This element comprises a bellcrank lever 41 pivoted on ahorizontal pin 42 mounted in an extension 43 formed in the punch block29, one arm of the bellcrank lever projecting into a transverse slot. 44out in the` punch block 29, this arm being rounded at 45 for engagementwith the upper end of the knockout rod 34. The opposite arm of thebellcrank lever 41 carries a cam roller 46, mounted on a pin 47 held inthe arm of the lever.

Other elements of the actuating devices com-V prises a stationarybracket 51 having slots 52 through which project studs 53 threadedlysecured to and projecting from the frame part 31. Suitable washers 54and locknuts 55 are employed for the purpose of clamping the bracket 51in adjusted position relative to the frame 31, the nuts 55 beingthreadedly secured to the studs 53 for this purpose. By this verticaladjustment of the bracket 51 and parts carried thereby, the actuation ofthe knockout pad 32 is delayed or advanced in time.

The bracket 51 carries a stud 56 on which is pivoted a cam plate 57 heldin operating position thereon by means of a washer 58 and a locknut 59.The cam plate 57 is slotted at 61 and a bolt 62 passing through the slot6l is threadedly secured to the bracket 51, this construction permittingpivotal movement of the plate 57 within the limits permitted by the slot61.

The cam plate 57 is normally eld in the position illustrated in Fig. 1by means of a spring 65 located in a transverse opening 66 formed in theplate 57, a spring barrel 67 having sliding movement therein andpartially enclosing the spring 65. The outer end of the spring barrel 67is adapted to engage the end of a setscrew 68 having threaded engagementwith the wall or" the bracket 51 and held in adjusted. position by meansof a locknut 69.

Under the action of the spring 65, the plate 57 is held in position withone end of the slot 61 engaging the bolt 62, this being the positionillustrated in Fig. 1. Adjustment of the screw 68 places more or lesscompression upon the spring 65 and Valies the resistance against pivotalaction of the plate on its bracket 51 for a purpose now to be described.

The cam plate 57 is provided with an inclined cam surface 71 which joinsa straight cam surface 72 and it is against these surfaces that theroller 46 moves as the press slide carries it up and down. Theinclinedsurface 71 is utilized under normal operation of the pressmechanism to oscillate the bell crank lever 41 about its pivot 42 anddepress the rod 34 and the knockout pad 32 in a knockout operation. Thespring 65 determines the amount of force delivered through the camroller 46 to oscillate the lever and actuate the knockoutinstrumentalities. In the event that abnormal resistance is met by theknockout pad 32 where such resistance becomes sufficient to overcome thespring 65, the latter yields and the cam plate 57 thereupon pivots onits stud 56, this moving of the plate preventing actuation of theknockout instrumentalities and avoiding damage to the press mechanism.

The material on which the press mechanism operates to produce a drawnarticle comprises a strip or sheet 75 which is fed over the lower diemembers 22, 23 and 24 in any suitable manner. There is illustrated inFigs. 1 and 2 a double thickness of material, this being an abnormalcondition obtaining when two sheets or strips 75 have stuck together andhave been fed into cutting andY drawing position. At such a time thepunch member 27 operating upon both sheets cuts and draws two articles76 which, owing to the increased thicknesses, become tightly jammed inthe opening 33 of the punch member 27 beneath the knockout pad 32.

Such a jammed condition oiers a resistance against movement of theknockout instrumentalities and it is then that the safety features or"the present invention become manifest. Accordingly, when the punchmember 27 is raised and the roller 46 moves from the cam surface 72 ontothe cam surface 71, the increased resistance against movement of theknockout instrumentalities holds the bellcrank lever 41 against movementon its pivot 42 and as the action of the spring 65 is overcome, the camplate 57 oscillates on its pivot 56 and moves from the positionillustrated in Fig. 1 into the position illustrated in Fig. 2.

This movement of the cam plate 57 prevents undue strain on the knockoutinstrumentalities and the bellcrank lever and damage to the die parts isthereby prevented. Other very important actions, however, follow as theresult of this movement of the cam plate 57.

In order to insure a holding of the cam plate 57 into its new position,there is provided a locking unit illustrated in detail in Fig. 3. Thecam plate 57 is provided with a transverse opening 81 in which ispositioned a spring barrel 82 threadedly engaged within the opening. Alocking pin 83 having an enlarged end 84 is urged inwardly by a spring85 surrounding the pin 83 and being interposed between the head 84thereof and a wall of the spring barrel 82. The outer-end of the pin 83carries a knurled head 86 which provides a ngerhold for the pin.

The bracket 51 is provided with a transverse opening 87 (Figs. 1 and 3)and as the plate 57 moves on its pivot 56, the `end 84 of the pin 83 isbrought into registration with the opening 87 and is `forced into it bythe spring 85 (Fig. 3). This locks the cam plate 57 in its new positionand further actuation of the bellcrank lever 41 can not take place untilthe abnormal conditions have been removed.

The cam plate 57, in moving to the position show in Fig. 2, electricallyinfluences the press mechanism by automatically stopping Vfurtheroperation. While this can be done in a number of diierent ways, there isdiagrammatically illustrated in Fig. 1 a wiring diagram exemplifying howthis may be accomplished.

An operating handle or arm 88 is the usual manual control for startingand stopping the machine and this is held in operating position by anelectro-magnet 89. This electro-magnet is normally energized from anysuitable source, as for example, a generator 91 supplying current whichnormally passes by means of a wire 92 and a wire 93, into theelectro-magnet 89 and thence by a wire 94 and a wire 95 back to thesource 1 of energy 91.

As soon as the cam plate 57 is shifted from its normal outermostposition (Fig. 1) into its closed position (Fig. 2) a shunt circuit isestablished which does not contain the high resistance found 1 in theelectro-magnet 89 and this diverts current from the electro-magnet,reducing the magnetic power of the same sufliciently, so that theoperating lever 88 thereupon falls from press operating position andstops the press. Mechani- 1 cally this is done as follows:

The upper end of the cam plate 57 is provided with an extension 96 inwhich is threadedly secured a sleeve 97 held in adjusted position by alocknut 98 and having a knurled thumb-screw 1 head 99. The sleeve 97contains a sliding contact pin 101, the head of which is engaged by aspring 102 held within the sleeve by a setscrew 103. This Contact pin101 is electrically in connection with the cam plate 57, the bracket 511 and the frame 3l of the press, these parts constituting an electricalground path. When in open position, this contact pin 101 is separatedfrom a contact plate 104 which is electrically insulated from the frameof the machine by an insulating 1 block 105. Plate 104 is connected witha binding post 106 to which is attached a wire 107 connected to the wire95 leading into the generator 91. A second wire 108 is connected betweenthe wire 92 and the frame 31 of the press.V g1

When the cam plate 57 is moved into closed position the contact pin 101is yieldingly engaged with the plate 104 and the shunt circuit isthereupon established, current at such time passing from thegenerato191, through wires 92 and 108, :245

normally passing through the electro-magnet 89 and this magnet thereuponbecomes deenergized, as previously described, allowing the handle 88 tomove into position for stopping the operation of the press.

Inasmuch as the locking pin 83 holds the cam plate 57 in its closedposition, the shunt circuit just described will continue to iow and cutout the operating lever holding circuit until such time as the parts arerestored to normal position. This is accomplished by withdrawing the pin83 from its locked position by engagment of the knurled head. Since thisis done manually, the abnormal conditions will have been rectified andnormal conditions restored prior to again manually starting theoperation of the press by movement of the handle 88.

The safety device is quick-operating and prevents pounding of the partsand destruction of the forming dies and the automatic locking featureinsures protection until the cause of the trouble is removed.

It is thought that the invention and many of its attendant advantageswill be understood from the foregoing description, and it will beapparent that various changes may be made in the form, construction andarrangement of the parts without departing from the spirit and scope ofthe invention or sacricing all of its material advantages, the formhereinbefore described being merely a preferred embodiment thereof.

I claim:

l. In a drawing press mechanism, the combination of cooperating dies forforming sheet material into articles, an anvil for drawing said materialinto one of said dies, a knockout rod having means for forcing saidmaterial out of the die, a

bell crank lever for actuating said rod, a movable cam plate foractuating said lever when itis held towards said lever, yielding meansfor so holding the cam plate, an electric circuit and magnet for keepingthe machine in operation, means operated by said cam plate for reducingthe energy in said circuit when the cam plate is actuated by said lever,and an automatic lock for the cam plate to maintain it in actuatedposition if it be released by said lever.

2. In a drawing pres-s mechanism, the combination of cooperating diesfor forming sheet material into articles, an anvil for drawing saidmaterial into one of said dies, a knockout rod having means for forcingsaid material out of the die, a bell crank lever for actuating said rod,a movable cam plate for actuating said lever when it is held towardssaid lever, yielding means for so holding the cam plate, an electriccircuit and magnet for keeping the press in operation, and meansoperated by said cam plate for reducing the energy in said circuit whenthe cam plate is actuated by said lever.

3. In a drawingpress mechanism the combination of cooperating dies forforming sheet material into articles, an anvil for drawing said materialinto one of said dies, a knockout rod having means for forcing saidmaterial out of the die, a bell crank lever for actuating said rod, amovable cam plate for actuating said lever when it is held in the pathof said lever, yielding means for so holding the cam plate, an electriccircuit and magnet for controlling the actuation of the press, and anelectric terminal on said cam plate for controlling said circuit.

ANTONE BERTUCCI.

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